Two Subwoofers... Comb Effect

Ok, points are definitely noted from those here responding about phase on the subs.
So here's some questions that even a novice might ask then. Which is, If phase doesn't matter on the subwoofers, in relations to each listner and the speakers, then why do subwoofers and even some processor offer phase adjustment in the first place? I mean, if you have one subwoower 3 feet from your listening position, and another 10 feet away, and maybe another 14 feet away from you, doesn't the phase get all confused and out of sync with the rest of your system?
I mean why does a full range speaker's woofer even have to be in phase with the rest of the drivers then? You mean it doesn't matter as long as you have relatively flat response from your sub-woofers, and proper volume level?
Maybe someone can address these questions concisely. Cause otherwise I think all the speaker engineers maybe put too much thought into making their large full range speakers so coherent in the first place. And not only that, but all the pre/pro's out there that have you specifying sub to listener position distance were just adding unnecessary steps to the process...

That's why I x-over as low as possible...40->45hz. And while my Sub IS fairly close to the LH speaker, it is still pretty seamless. Don't forget that recordings. ..with the possible exception of the Telarc recording of Wellingtons Victory are MONO below about 80hz.
The Telarc disk has very localized CanonShots which are a real system test.
SMALL point...using 1ms/ft is probably OK, but sound is actually a little quicker....maybe 14"/ms....like a said, a very small point......

Phase matters alot

There is a 180 degree phase shift in the bass phase anyway - which happens across resonance. So the whole thing is debatable however but purists will argue that even the 180 degree shift is bad - so it is best to get resonance way down and ultimately a system Q of 0.3 to 0.5 will give a better transient response (unfortuntely very inefficient in terms of SPL output).

See this article which explains the trade offs of small light weight woofers with small magnets in ported boxes (cheap - great extension but poor transient response) versus big heavy woofers with large magnets in sealed boxes.

The author says:

"There thus evolved two camps of woofer design: those with strong magnets, having better transient accuracy but worse LF response [he means poor LF extension], and those with weaker magnets having good LF response [better LF extension] but poor transient response. However, the poor transient response of a sealed box with a woofer having a weak magnet pales into insignificance alongside the wholesale demolition of the waveform that takes place in reflex, bandpass and transmission line speakers."

=> this may explain why small ported speakers with impressive bass extension just do not sound right with percussion (at least to my tin ears).

Phase matters alot

If you feel that way then consider active designs with digital filters - manufacturers can correct phase in the crossover region as well as below woofer resonance in the bass...yes you heard me correctly it means "perfect phase". I am not sure if Meridian do this but mathematically it can be done. As far as I know ATC do not specifically correct phase in the bass roll-off but they do so in their active crossovers and overall the speaker is phase adjusted as a whole using analog electronics.